You know who they didn't interview: those who regret saving so much. Many of those people are dead and so the regret is something we can only apply on assumption that they would. I've known a few people who unexpectedly died before they hit retirement age. I've know a few people who retired and died suddenly. The vast majority of people in a "first world" country have an expected lifespan of about 80 - but there is a statistical curve and people start dieing in significant numbers at 65, while you are not an outlier until you make it to near 100 (though some exist).
You need to have some emergency savings. You should save for retirement somehow. If you can structure the above as insurance - and you can trust the insurance - (I know a few cases where the insurance type system went bankrupt and those with a "policy got nothing") that is best.
Once the above is taken care of though, you can't take it with you (at least in most religions) so spend it. Save enough, but not too much.